#Amiga dms disk archive software#
#Amiga dms disk archive code#

DMS was very popular in the software pirate and demo scenes. The past and present stateĭMS format was originally used by Amiga computers for disk data archiving. To address this issues different archiving methods were developed that employed alternative reading and compression solutions, such as xDM and XAD. Unfortunately, DMS format has problems with storing some bit sequences due to errors in compression algorithm it uses. The format natively supports compression and offers some copy protection solutions. While creating a DMS file the source disk is read block-by-block to maintain the data structure. DiskMasher is a copyright-protected format. DMS file stores compressed disk image (usually floppy) for Amiga computers. I did all my development in that monitor.DMS (DiskMasher) file extension is used by Amiga disk image files generated with The Disk Masher software tool. So totally chuffed that I can use an Action Replay in Vice. Oh yes, make sure you disable any fastloaders and enable true drive emulation in Vice when using these tools. Gave me a fright to think there was such an obvious bug in my code…

#Amiga dms disk archive code#

I loaded an Action Replay cartridge and used the monitor in that to view the same code in Vice where the BNE address is correct. The first screenshot below is from CBMXfer and you’ll notice that the BNE returns to the wrong address. While looking at the ASM code in the file DMSREAD I think I found a small bug in the otherwise excellent CBMXfer. The original file has been renamed DMSREADER.ORIG. The DMSWRITER BASIC loader uses 56321 which is correct, but I have to wonder why I didn’t use a BASIC command to wait for a key press rather than fooling around with low level registers. I replaced CC with 34 (character “4”) to get a code listing. Look for 8F CC in the screenshot below of the Action Replay machine code monitor. Just so I could debug the programme itself I had to edit the RAM where it lived and replace that character. To stop people looking at the code I added REM commands followed by an illegal character. When I wrote that BASIC programme I was too smart by half. Fixing it was easy, replacing the following code:ġ000 IF (PEEK ($DC01)AND $10) 0THEN GOTO 1000 Unfortunately when I first tested the reader I received a “?SYNTAX ERROR IN 1000” error just after I was told to flip the destination disk. There’s still a bug in the READER where it asks you to flip the destination disk a second time, ignore that and just hit space. You’ll have to use two destination disks unfortunately as I never got around to compressing the output files. The source drive should contain the disk you want to make an image of and the destination will be a blank disk. The process is much the same, only in reverse. I never noticed any problems previously so hopefully it’s a false alarm.ĭMSREADER is responsible for creating DMS files. I need to make sure that isn’t the case or we’ll end up with corrupted disks. I also noticed the text of the on screen display flashes up while writing as if that data is written to disk. I noticed that the source drive light continues to flicker after the process is over but sending a reset or loading the disk directory will sort that out. When data is written to the destination disk the border flashes with thick multicolour bars but when it flashes quickly with a grey/blue flicker you need to change the source disk to feed it more DMS files. Where I wrote “destination disk” in the DMSWRITER it should have been “source disk” instead. Enter your drive number(s) and follow the instructions. By the looks of things I used some sort of illegal character trick to hide the BASIC loader but you can view it easily in CBMXfer.ĭMSWRITER recreates the disk from the DMS files. Each of the two parts are a mixture of BASIC and assembly language. It’s obviously not that useful these days when a D64 image file is only 171KB but for historical reasons it’s probably of interest. Some of my demos are already on CSDB but not this. I’m posting this here because there’s no sign of this tool at all online. It’s an address I had in first year in college and is long gone! Don’t bother trying to send a message to the email address in the note. They could only be useful to users of higher capacity disks anyway.

Were D64 image files around in 1994? If they were I didn’t know about them. The purpose of the tool was to create an image of 5 1/4 disks but break the image up into smaller DMS files.Īccording to the attached note, I wrote it to upload C64 demos to local BBSes but it was also used by me and the few people I still swapped C64 disks with back then. I presume I got the name from the Amiga DMS tool but I really don’t know. DMSREADER and DMSWRITER are two parts of a Commodore 64 tool I wrote way back in 1994.